In the communications field, particularly in radio communications, transmission time is desirably maintained at a minimum. In radio communication, the available channels are crowded and there is great competition for air time. For this reason most paging systems involve the transmission of messages in digital format because the digital format requires less time to transmit. The messages received, however, are limited to short written messages which are displayed on a small LED or LCD display screen and the messages are normally limited to the type that require the subscriber to go to a telephone and call the message originator. In addition to the limited message capability of such systems, the transmitting components are expensive, normally requiring centralized computer message facilities to transmit the digital data and to store the analog messages for the subscribers.
Accordingly, it would be highly desirable to provide a system for transmitting analog messages directly to a remote unit in which the analog messages are transmitted at a high rate of speed to conserve air time and are received and recorded at the remote unit for playback at a slower rate of speed to return the message to its audible condition. As a corollary, it would also be desirable to transmit certain analog data at a slow rate of speed and to play the message back at a higher rate of speed, again to return it to its audible format. Such a transmission procedure is beneficially carried out in the transmission of music and other high fidelity analog data over telephone lines which normally adversely affect the fidelity of the data being transmitted. In such a case it would be desirable to transmit the data at a slow rate of speed thereby to retain the fidelity and to play it back at its normal rate of speed without loss of fidelity.